diff --git a/.github/scripts/python.sh b/.github/scripts/python.sh
index a71e14c974..80f5312299 100644
--- a/.github/scripts/python.sh
+++ b/.github/scripts/python.sh
@@ -43,7 +43,7 @@ if [ -z ${PYTHON_VERSION+x} ]; then
     exit 127
 fi
 
-PYTHON="python${PYTHON_VERSION}"
+PYTHON="python${PYTHON_MAJOR_VERSION}"
 
 if [[ $(uname) == "Darwin" ]]; then
     brew install wget
@@ -66,7 +66,8 @@ mkdir $GITHUB_WORKSPACE/build
 cd $GITHUB_WORKSPACE/build
 
 cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=Release \
-    -DGTSAM_BUILD_TESTS=OFF -DGTSAM_BUILD_UNSTABLE=ON \
+    -DGTSAM_BUILD_TESTS=OFF \
+    -DGTSAM_BUILD_UNSTABLE=ON \
     -DGTSAM_USE_QUATERNIONS=OFF \
     -DGTSAM_WITH_TBB=${GTSAM_WITH_TBB:-OFF} \
     -DGTSAM_BUILD_EXAMPLES_ALWAYS=OFF \
diff --git a/.github/workflows/build-python.yml b/.github/workflows/build-python.yml
index 3f9a2e98ac..e4eafe920c 100644
--- a/.github/workflows/build-python.yml
+++ b/.github/workflows/build-python.yml
@@ -12,6 +12,8 @@ jobs:
       CTEST_PARALLEL_LEVEL: 2
       CMAKE_BUILD_TYPE: ${{ matrix.build_type }}
       PYTHON_VERSION: ${{ matrix.python_version }}
+      PYTHON_MAJOR_VERSION: 3
+
     strategy:
       fail-fast: false
       matrix:
@@ -26,32 +28,37 @@ jobs:
         ]
 
         build_type: [Debug, Release]
-        python_version: [3]
+
         include:
           - name: ubuntu-18.04-gcc-5
             os: ubuntu-18.04
             compiler: gcc
             version: "5"
+            python_version: 3.6.9
 
           - name: ubuntu-18.04-gcc-9
             os: ubuntu-18.04
             compiler: gcc
             version: "9"
+            python_version: 3.6.9
 
           - name: ubuntu-18.04-clang-9
             os: ubuntu-18.04
             compiler: clang
             version: "9"
+            python_version: 3.6.9
 
           - name: macOS-10.15-xcode-11.3.1
             os: macOS-10.15
             compiler: xcode
             version: "11.3.1"
+            python_version: 3.9.1
 
           - name: ubuntu-18.04-gcc-5-tbb
             os: ubuntu-18.04
             compiler: gcc
             version: "5"
+            python_version: 3.6.9
             flag: tbb
 
     steps: